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At least 919 records · Page 51Linked to original sources
PubMed2003

Plasmacytoid cells in salivary-gland pleomorphic adenomas: evidence of luminal cell differentiation.

To determine the cellular origin of plasmacytoid cells in salivary gland adenomas, immunohistochemistry was performed on sections from 12 pleomorphic adenomas rich in these cells. In normal salivary glands included in these sections, the myoepithelial cells (MECs) expressed alpha-smooth muscle actin (alphaSMA) and smooth muscle myosin heavy chain (SMMHC), whereas the duct luminal cells expressed keratins 19, 18 and 8. Some of the salivary duct basal cells expressed these keratins, and the acinar cells expressed keratins 18 and 8. The expression profile was similar in rat salivary glands not only after but also during development. The immature MECs never expressed the keratins nor did the immature duct cells express alphaSMA. In seven cases, up to 60% of the plasmacytoid cells expressed keratin 19. In three of these cases, about 10% of the plasmacytoid cells expressed keratin 18. No plasmacytoid cells expressed alphaSMA, SMMHC or keratin 8. These results indicate that plasmacytoid cells originate from luminal cells and not from MECs. Furthermore, in addition to the luminal tumor cells, the non-luminal cells could express keratins 19, 18 and 8. Therefore, it is necessary to re-evaluate the prevailing notion that non-luminal cells are modified MECs. Keratin 14, basic calponin, vimentin and p63 were bi-specific for the MECs and the duct cells. Therefore, expression of these proteins by significant numbers of the non-luminal tumor cells and the plasmacytoid cells never denied the above notion.

Adenoma, Pleomorphic↗
PubMed1997

Effect of spatial arrangement of the basement membrane on cultured pleomorphic adenoma cells. Study by immunocytochemistry and electron and confocal microscopy.

In a cell line from human pleomorphic adenoma (AP2 cells) we studied the response of these cells to basement membrane proteins. The culture was characterized as myoepithelial-like by transmission electron microscopy and immunocytochemistry. AP2 cells were grown in contact with a reconstituted basement membrane (Matrigel). Cells grown on Matrigel showed conspicuous phenotypic alterations, depending on how the substrate was applied. Cells grown on the top of Matrigel developed a dendritic phenotype, exhibiting thin, long and intercommunicating cytoplasmic extensions resembling normal myoepithelial cells. Cells grown inside Matrigel formed multi-layered clusters. Light, confocal and transmission electron microscopy showed that these clusters were formed by double-layered epithelioid cells delimiting luminal spaces. The cells facing the lumen were cuboidal, showing microvilli at the apical plasmalemmal and junctional complexes. The spatial arrangement of basement membrane is a key modulator of morphogenetic changes and cytodifferentiation of tumour myoepithelial cell lineage in culture.

Adenoma, Pleomorphic↗
PubMed1999

Oncocytic myoepithelioma and pleomorphic adenoma of the salivary glands.

Twenty oncocytic myoepitheliomas (MEs) and pleomorphic adenomas (PAs) were composed of interlacing fascicles of swollen spindle-shaped or/and epithelioid oncocytic myoepithelial cells showing intense finely granular immunoreactivity with anti-mitochondrial antibody. Focal vacuolation of the cytoplasm of oncocytic myoepithelial cells and their gradual transition into sebaceous metaplasia were observed in 3 cases. Another unusual feature found in 5 cases was the presence of slit-like adenomatoid spaces lined with double-layered oncocytic myoepithelium closely resembling Warthin's tumour. The nuclei of oncocytic cells were characterized by enlargement, hyperchromasia and polymorphism, which should not be confused with malignancy. Oncocytic change in myoepithelial cells in MEs and PAs can cause pitfalls in the differential diagnosis of salivary gland tumours. We describe some unusual histological features associated with onococytic metaplasia in benign myoepithelial cell-derived salivary gland tumours, hoping to help to avoid the overdiagnosis of malignancy.

Adenoma, Pleomorphic↗
PubMed1989

Ultrastructural morphology of secretory granules in pleomorphic adenoma of human parotid and submandibular salivary glands.

Secretory granules were found in some of the cells lining the lumina of typical epithelial structures in pleomorphic adenomas. They were small, of varied electron density, and were mostly unipartite, sometimes bipartite and occasionally tripartite. They most closely resembled secretory granules of intercalary ductal cells of normal salivary glands.

Adenoma, Pleomorphic↗
PubMed1977

Pleomorphic adenoma of the nasal septum.

A brief review of the world literature on pleomorphic adenoma of the nasal septum is presented. One further case is reported, treated by surgical excision via lateral rhinotomy. Alternative surgical approaches are considered.

Adenoma, Pleomorphic↗
PubMed1988

Recurrent pleomorphic salivary adenoma--the relevance of age at first presentation.

All cases of pleomorphic salivary adenoma treated at the West of Scotland Regional Plastic and Oral Surgery Unit, Canniesburn Hospital, over the 10-year period 1974-1983 have been reviewed. Nearly one-fifth of patients were treated for recurrence. These patients presented with their primary tumour at a significantly younger age (p less than 0.001) than those who remained disease-free. Sixteen of 31 who subsequently developed recurrence were under 30 years of age at initial presentation. Of all patients under 30 years of age at first presentation, 42% subsequently developed recurrent diseases.

Adenoma, Pleomorphic↗
PubMed1975

Radiologic features of benign pleomorphic adenoma of the hard palate.

The clinical and radiographic features of two cases of pleomorphic adenoma are discussed. With the use of hypocycloidal tomography, definitive radiographic signs of benignity are demonstrated. They include (1) a radiolucent defect with well-defined cortical margins; (2) beveled margins which describe an intraoral origin of the neoplasm; (3) confinement of the neoplasm within the actual osseous defect, or within the projected circumferential diameter of the defect, if complete erosion has occurred; and (4) lack of periosteal reaction or osseous involvement of the hard palate adjacent to the radiolucent defect.

Adenoma, Pleomorphic↗
PubMed1980

Histochemistry of glycoconjugates of pleomorphic adenomas of minor salivary glands, with special reference to glycocalyx of tubular areas.

Histochemical characterization of glycoconjugates elaborated by palatal pleomorphic adenomas showed that glycoproteins, glycosaminoglycans, and perhaps glycolipids were present in both the "epithelial" and "connective tissue" components of these tumors, as well as in the distinct glycocalyx present in the luminal surface of tubular and cystic areas.

Adenoma, Pleomorphic↗
PubMed1990

No rearrangement of c-mos in salivary gland pleomorphic adenomas with 8q12 aberrations.

The frequent occurrence of salivary gland pleomorphic adenomas characterized by clonal structural chromosome abnormalities involving 8q12 raises the question as to how the cytogenetic rearrangements correspond to molecular mechanisms of tumor development. Since the proto-oncogene c-mos maps to this breakpoint region, DNA from eight adenomas with these aberrations was isolated and checked for rearrangements of c-mos after digestion by BamHI, EcoRI and HindIII. In none of the tumors was a rearranged allele besides the germ-line fragments found.

Adenoma, Pleomorphic↗
PubMed1996

Mapping of the translocation breakpoints of primary pleomorphic adenomas and lipomas within a common region of chromosome 12.

Recent molecular cytogenetic analysis of uterine leiomyoma cell lines with chromosomal aberrations of 12q14-q15 have indicated that the chromosome 12 breakpoints cluster in a 445-kb region designated ULCR12 (uterine leiomyoma cluster region of the chromosome 12 breakpoints). Here we report the results of FISH studies of five primary pleomorphic adenomas and six primary lipomas and established cell lines of these tumor types characterized by translocations involving the chromosomal segment 12q13-q15. The results reveal that for nearly all tumors and cell lines analyzed, the chromosome 12 breakpoints map within a 350-kb region included in ULCR12, despite the previous cytogenetic assignment of the breakpoints to different bands of that region. In some cases the primary material and additionally analyzed cell lines allowed an even more precise localization of the breakpoints to less than 100 kb. Furthermore, a previously hidden translocation of ULCR12 in one primary tumor could be detected by FISH.

Adenoma, Pleomorphic↗
PubMed1990

Management of the parotid pleomorphic adenoma, the problem of exposing tumour tissue at operation. The logical pursuit of treatment policies.

The objective of treatment of a parotid pleomorphic adenoma is to remove all tumour cells with minimal short- and long-term morbidity and minimal recurrence rates. If an enucleation is carried out, the facial nerve may be put at risk and tumour fragments will inevitably be left in the wound. Most surgeons suggest that after enucleation, radiotherapy must be given to reduce the recurrence rate to an acceptable level. If during a formal superficial parotidectomy the tumour capsule is visualised, the objective of removing the tumour with an intact cuff of normal tissue has failed and the operation has in effect become an enucleation. This paper defines the problem and discusses its management.

Adenoma, Pleomorphic↗
PubMed1990

Familial occurrence of pleomorphic adenoma of the parotid gland.

Two cases of pleomorphic adenoma of the parotid gland occurring in brothers are presented. The seven previous reports of familial salivary gland tumours are tabulated and the aetiological associations of salivary gland neoplasia are reviewed.

Adenoma, Pleomorphic↗
PubMed1987

Nodular hidradenoma: an eccrine sweat gland analog of pleomorphic adenomas of salivary gland origin.

A tumor of eccrine sweat gland origin is described that bears a striking resemblance to pleomorphic adenomas of salivary gland. Upon closer examination, the tumor contained areas of apocrine decapitation secretory activity, primitive hair follicles, and melanin pigmentation, indicating cutaneous rather than mucosal origin. Six-month follow-up examination has revealed no evidence of recurrence.

Adenoma, Pleomorphic↗
PubMed1989

Radiation therapy in recurrent pleomorphic adenoma of the parotid.

Twenty-nine patients were treated by excision and post-operative irradiation following recurrence of pleomorphic adenoma (mixed tumor) of the parotid. Eighteen of 20 (90%) patients with a first recurrence were controlled comparing favorably with series employing surgery only. Radiation therapy has a role to play as a surgical adjuvant in the management of these tumors, in particular when surgical difficulties are encountered and for second or subsequent recurrences.

Adenoma, Pleomorphic↗